Driving mechanism



c. F. GlLcHRlsT 1,776,115

DRIVING ucmmrsl l `Original Filed July 22, 1918 llrtowuL Patented Sept. 16, 1930 DRIVING MECHANISM Application filed 'July'za v1918, serial j This invention. relates to a driving mechanism for use in the starting system of an internalcombustion engine. More particularly considered,.the invention comprises an automobile screw gearing applicable in the gear train intermediate the electric starting motor and internal combustion engine.

The principal object of this invention is to provide a driving mechanism intermediate the electric motor and engine which has iexibilityand elasticity, and in which there is no spring or similar elastic member in the direct line of power transmission. l

Another object is to provide a type of gearing in which the driving connectiongand jdisconnection is made in an entirely automatic way.

Another object is to utilize a gearing unit which will automatically take care of variations in engine cylinder compression.

Further objects of this invention relate to economies'of manufacture andidetails of construction as will hereinafter appear from the detailed description to follow. I accomplish the objects of my invention in one instance b the devices 'and means described in the fol- .lowingspecificatiom but it is evident that the f same may be varied widely withoutdeparting from the scope of the invention as pointed out i in the appended claims. A structure constituting one embodiment of `my invention, which may be the preferred, is villustrated in the accompanying drawing forming a part thereof, inw'hich: l

Fig. I is a longitudinal sectional view taken through the gearing unit showing it in its disconnected position.

Fig. II is a view similar to Fig. I but showingthe gearing unit in its connected position, certain parts being shown in elevation. 4

Figures III, IV and V are cross sectional views taken' respectively on the lines 1111+111, 1v-1v and v v 0f Fig. 1.

Similar referencenumerals refer to similar parts throughout the several views, and the cross sections are taken looking in the'direction of the arrows.

As illustrated, the shown as forming motor 1, having a driving mechanism is part of an 'electric starting driving shaft 2, the outer sleeve 4,'at its outer end, is slotted in su' the direction' of rotation 110.2463188. Renewed .nii'yfaa` ieee.

end 3 of which'is threaded for a purpose hereinafter described. Mountedyupon the 'shaft 2, and adapted foraxial movement'tliere'- upon, is a sleeve 4 which is'threadedyfo'r'a portion of its length, as indicated at 5. Internally threaded,` so as t'o'mesh with th'ethre'ad upon the sleeve, is a pinion 6, whichpreferably has a `counter-Weight 7, and which is offset longitudinally at 8. Inl'order to hold the lpinion at the outward'limit of itsmove ment, there is utilized a tensioning y'spring 9, which is mounted upon a pin 10, 'placed in termediate the offset portion of the counter# weight and the sleeve.v There is a coll'arll on the pin, and between this collar and the coun-V ter-we`ight, the spring exerts pressure so that when the pin is outside the outer thread the pinion is held from inward Inoveme'ntuntil a suiciently large force is applied thereto, thereby keeping the pinionin yproper 'adjust` ment relative to the sleeve 4. j

he pinion is ad pted to have axial'move ment along the sleeve, so as to' permit lits en meshment with the gear 12, which gearis diy rectly connected to the crank shaft `ofthe engine, and in the arrangement commonly used orms the tly-whee1 of the engine. ,'Upon the' inner end of the sleeve is a stop 13 for limiting themovement of the pinion when it is in mesh with the' gear 12. f .I ,Y l

As shown in FigureV of the'drawing, the

Ah a way as to form four slots 14, situated at right angles l to Veach other around the circumference of the sleeve'.Y Adapted.tohavefscrew thread engagement withy the threadedy portion of the lshaft ofthe mot-0r, is anut 15 iof circular cross section `,as indicated inFigure III. Keyways 16 are cut in this nut,and keys r17 inserted,.and theseekeys' are adapted to have axial movement inextended keyways 18,'cut onth'e interior offa tubular casing A19, so that" motion may bev transmitted continuously in of rthe nut, simultaneously with axial movement thereof. The casing 19`has at its opposite end an inwardly extending lflange 20 which has .fourinwardl'y extending Ilugs 2l `enga'ging' in the slots Q14 of the sleeve. A washer 22 1s secured over "the sleeve so as to prevent inward movement of the casing 19.

In the annular space between the casing and the sleeve is a coil spring 23 whose one end abuts against the flange and Whose other end abuts against the nut 15 and is adapted to retard the movementof the units in an inward direction. Outward movement of the nut 15 is prevented beyond the terminal of the shaft .by a washer24ra-nd nut 25, y

andthe inner-movement of the nut15 is limited by the end of the sleeve 4 which extends within the casing to a pointadjacent the inner end of the keyways 18.

In the operation of this driving mechanism, power is transmitted from the motor through Vthe shaft2, to'the nutY 15. .Inass much asfth'ere is ascr'ew connection between the motor shaft vand nut, there will be a tendency of the nutto screw inwardly on the shaft, but oppositionof this movement is afforded by the spring, and inasmuch as, initially, there is noload on the pinion 6, inf,

ward motion of lthefnut is practically absent.

From the nut, transmission is extended through the guide casing 19 to the sleeve 4,

so that there' is rotation of all movable parts uponI the shaft, with the exception ofl pinion 6, which, because of its inertia, moves without rotationaxiallyinto mesh with the'.

gear. As soon as the complete `mesh withV and ispreventedfrom pinion v has come into further 5 axial movement by the stop 13,' the pinion will imme-V diatelyjattempt to take up the rotative speed of the shaft. If there were no resilient elements in the drive assembly, the immediate effect of the sudden starting of the pinion would be disastrous,pre'sulting, very likely, in stripping the teeth of the pinion and gear.

However, when axial movement of the pinion y.

is prevented by the stop, the sleeves: and

casing 19 immediately cease rotationl and the motor shaft screws intofthe nut 15, thereby causing it to travel inwardly along the motor shaft against the expansive force of the coil spring until it finally comes in contact with theouter end of the sleeve 4f By this means, the shock of the sudden start` is obviated and the pinion assumes the speed of the motor shaft through' a gradual increasein the ap-V plied force, the greater part ofthe Vshock being taken up by the 'coil spring;v

In the event that they pinion 6 fails to properly meshvwith the gear, the sleeve will travel bodily outward, carryingl the-casing 19 with it, against the compressionof the spring. y This will permit suiicient rotation of the pinion, so as to cause it to properly mesh with the gear and prevent any disastrous effects.

It should be particularly noted-that the spring in this drivingassembly is not in a direct line of transmission, but serves merely to absorb the `shock due to suddenimpression the gear wheel *12,`

of the load on the pinion. There is, therefore, no tension upon the spring which operates under compressiononly, thereby lessening to a marked degree the chances of failure in operation of the mechanism.

I am aware that the specific embodiment of my invention herein' shown and described is susceptible of considerable variation without departing from the spirit of my 'invenfl tion, and, therefore, I desireto claimj the 'same broadly as 4wellas specifically,*as' indicated by the appended claims.

Havingtlius described my invention, I claiinlas new and desiretosecure by Letters Patent is:- l d 1.: In afdriving mechanism for starting motors, Athecombination of a` gear operaeL vtively connected to a'n engine; a driving shaft, the outer portion of which is threaded; a threaded sleeve on said shaft, having a gi'ooved outer portion; an internally threaded pinion on saidfsleeve adapted to move ax-l sleeve and to engage said grooved outer portion; acoiledspring intermediate the nut and the flanged end'fof, said casing; andmeans forlimiting the axial movement of thenut. I 2. In a driving mechanism for starting motorsthecombination of a; gear operativelycconnected .to an internal combustion' engine; a driving shaft, the outer portion of which is threaded; a nut having threaded engagement with the threaded portion 'of the shaft; angexternally threaded sleeve mounted on theshaft, the outer end of said sleeve serving as a limiting stop for lthe nut; a` casing inclosing the threaded portion of the shaft,

what

the inner end of which has lugs bearing on and- Yinlengagement with thesleeve and the outer end, of which `has keyways` cut on its inner surface forming a bearing for the nut; aspring, interposed between theznut andthe `end lugs ofthe casing;,and a pinion .having threaded 4engagement withV the sleeve and Amovable axially into enmeshment with saidV gear. Y

In a driving mechanism .forf startingmotors, the combination of a gear operatively connected to an internal combustion engine;

a driving shaft,-=the outer portion of whichV is threaded; .a `nut having threaded engagement with the .threaded portion of the sha-ft;

an externally threaded-sleeve mounted on the shaft, the outer end of'said sleeve serving as av limiting stop for the nut; means forming va driving connectionbetween said sleeve and said nut, thenuthavingan vaxial sliding enj gagement with said means; a spring on said .Y

shaft adaptedrto yieldingly oppose the axial movement ,of said-nut; and al pinion having threaded engagement'with said' sleeve and ing on said driven axially into engagement flanged to form a bearing, and to engage saidv grooved outer portion of said sleeve; a coiled spring intermediate said nutandthe flanged end of said casing; and means for limiting the axial movement of the nut.

In a driving mechanism for engine starting motors, the combinationof a driving shaft, a driven shaft freely mounted upon the driving shaft, a pinion having a threaded mounting on said driven shaft and movable relative to the driven shaft into engagement with the engine member, a casing slidably mounted on said driven shaft, and a slidable connector forming a driving connection between the driving shaft and casing, said connector having a screw threaded bearing on the driving shaft.

6. In a driving mechanism for starting motors, the combination of a driving shaft, a driven shaft freely mounted upon the driving shaft, a pinion having a threaded mountshaft and movable axially relative to the driven shaft into engagement with the engine member, a casing slidably mounted on said driven shaft, a slidable connector between the driving shaft and casing having a screw threaded mounting on the shaft, and resilient means normally tending to resist slidable movement of said slidable connector and casing, said connector forming a driving connection'between the casing and shaft.

7. In a driving mechanism for starting motors, the combination of a driving shaft, a driven shaft freely mounted upon the drivin@ shaft, a pinion operatively mounted on an adapted to be rotated by said driven shaft movable axially relative to the driven shaft into engagement with the engine member, a casing slidably mounted on said driven shaft, a slidable connector forming a driving connection between the driving shaft and casing having a screw threaded mounting on the shaft, and resilient means normally tending to resist slidable movement of said slidable connector and casing, the end of saidV driven shaft forming a limiting stop for movement of the slidable connector.

8. In a drive mechanism, a driving shaft having a threaded portion, a driven shaft freely mounted on the drive shaft, a pinion mounted on said driven shaft, a member operatively connected to the ldriven shaft, and a connecting member having screw-threaded engagement with the threaded portion of the drive shaft and slidable engagement with the first named member.

9. In a drive mechanism, a drive shaft, a driven shaft, a pinion mounted on and movable on said driven shaft adapted to be rotated thereby, and a plurality of separate sliding members interposed between said driving and driven shafts, one of said members being axially slidable relative to the other member and having a screw threaded connecItion with the drive shaft.

a driven shaft, a pinion mounted on and movable yon said driven shaft adapted to be rotated thereby, a plurality of f separate sliding members interposed between said driving and driven shafts, one of said members being axially slidable relative to another, and both members being movable relative to the drive shaft, one of said members having a screw threaded mounting on the drive shaft.

1l; An'engine starter comprising in combination, a plurality of threaded elements; driving means for one of said elements; a pinion carried by the other of said threaded elements; a member connecting said threaded elements, said member having a lost motion connection with one of said elements; and means including a spring cooperating with said member to form a yielding driving connection.

l2. An engine starter comprising, in combination, a driving shaft having a threaded portion; a relatively movable member cooperating with the threaded portion of said driving shaft; an independent threaded element; a pinion Ladapted for longitudinaland rotarymovementcarriedbysaidthreaded element; a resilient element interposed between said member and said threaded element for establishing yielding driving connection between said driving shaft and said threaded element.

13. An engine starter comprising, in combination, a driving shaft; a member carried n a drive mechanism, a drive shaft,l

by said shaft and movable thereto; a thread- 

